Tripoli, Libya — Military forces loyal to Libyan leader Muammar Qaddafi shelled antigovernment rebels Wednesday, deepening the confrontation over a critical front line while Mr. Qaddafi vowed that victory would ultimately be his.

So far rebels have shown little ability to take advantage of five days of American and European air and missile strikes aimed at erasing Qaddafi’s offensive capabilities.

“This assault … is by a bunch of fascists who will end up in the dustbin of history,” Qaddafi proclaimed in his first public appearance since allied strikes began March 19 under a United Nations mandate to protect civilians from advancing government units.

“We will defeat them by any means…. We are ready for the fight, whether it will be a short of a long one … we will be victorious in the end,” Qaddafi vowed.

The air strikes put pressure on Qaddafi in Misratah, the last rebel-held western city, which government forces have encircled for days despite the UN mandate to withdraw.

News reports from the eastern front, meanwhile, indicated that forces loyal to Qaddafi began the firing upon rebel militiamen Wednesday from the besieged city of Ajdabiya, which is a key stop on the road to the rebel stronghold of Benghazi.

Rebels reportedly complained that they were outgunned in Ajdabiya. In recent weeks, Qaddafi's forces abruptly halted and reversed the rebels' westward momentum, pushing them back to Ajdabiya and then even threatening Benghazi itself until the allied air campaign began on Saturday.

Tripoli has declared at least two cease-fires, but they were not announced by Libyan state broadcasters and have patently not been respected on the ground. Qaddafi dismisses the opposition as “rats” and Al Qaeda “terrorists” addled by drugs, and says the US should be on his side as he tries to wipe them out “house by house.”

A government activist in Tripoli claimed midday that he had just received a call from a soldier at the Ajdabiya front.

“He complained that we [pro-Qaddafi forces] are following the cease-fire, and everyday these rebels attack us,” said the activist.

“We have a problem: If we attack, the French and Americans will attack us. But if they attack, we must take cover,” he said the Libyan soldier told him. That account directly contradicted reports from the front, which say Qaddafi forces have sought to press the advantage at every opportunity.